The present invention relates to an ozone purifying apparatus for purifying ozone (O3) in atmospheric air, and particularly to an ozone purifying apparatus mounted on a vehicle.
When a vehicle is running, air flows across the surface of a vehicular body or across the surface of a radiator mounted in the vehicle. As such, an ozone purifying apparatus has been proposed including ozone purifying catalysts spread on the surface of the vehicular body or the surface of the radiator, thereby purifying ozone in atmospheric air. For example, Japanese Patent Publication (Published Translation of PCT application) No. Hei 11-507289 corresponding to International Publication No. WO96/22150. The ozone purifying apparatus is intended to suppress the occurrence of photochemical smog by purifying ozone in atmospheric air.
The above-mentioned ozone purifying apparatus however, has disadvantages. For example, if extraneous matter such as dust particles having a size on the order of several micrometers adheres to the surface of the ozone purifying apparatus, the particles may permeate and thereby clog a catalyst layer, obstructing the diffusion of ozone in the catalyst layer or reducing an amount of ozone coming into contact with the catalysts. Accordingly, the amount of ozone purified by the catalysts is reduced and the purifying ability of the ozone purifying apparatus is degraded.
Another disadvantage is that the purifying ability of the ozone purifying apparatus may be degraded by sulfur oxide (SOx) or the like in atmospheric air.
An object of the present invention is to provide an ozone purifying apparatus capable of detecting the degradation of ozone purifying means, such as ozone purifying catalysts, due to various causes, for example, the degradation due to adhesion of extraneous matter or the degradation due to SOx.
To achieve the above object, there is provided an ozone purifying apparatus for a vehicle, comprising: heat radiating means provided on the vehicle; ozone purifying means carried on the surface of the heat radiating means; estimating means for estimating an amount of adhered matter adhering on the ozone purifying means; and diagnosing means for diagnosing the operating state of the ozone purifying means according to an output from the estimating means.
With this configuration, an amount of adhered matter adhering to the ozone purifying means is estimated and the operating state of the ozone purifying means is diagnosed according to the estimated amount of the adhered matter. Therefore, it is possible to diagnose an adhesion state of adhered matter such as dust on the ozone purifying means and hence to detect degradation of a purifying characteristic of the ozone purifying means, and to give a warning to the driver of the vehicle.
According to a second aspect of the present invention, there is provided an ozone purifying apparatus for a vehicle, comprising: heat radiating means provided on the vehicle; ozone purifying means carried on the surface of the heat radiating means; airflow detecting means for detecting an amount of airflow passing through the heat radiating means; and diagnosing means for diagnosing the operating state of the ozone purifying means according to an output of the airflow detecting means.
With this configuration, an amount of airflow passing through the heat radiating means is detected and the operating state of the ozone purifying means is diagnosed according to the detected amount of airflow. Therefore, it is possible to diagnose an adhesion state of adhered matter such as dust on the ozone purifying means and hence to detect the degradation of the purifying characteristic of the ozone purifying means, and to give a warning to the driver of the vehicle.
The estimating means preferably includes at least one of a contamination measuring plate allowing light to pass therethrough and a contamination measuring plate allowing light to be reflected therefrom, the at least one of contamination measuring plates being disposed in the vicinity of the heat radiating means; a light emitting means for irradiating the at least one of a contamination measuring plate with light; and a light receiving means for detecting a quantity of light passing through or being reflected from the at least one of a contamination measuring plate.
The estimating means preferably includes an air passage disposed in the vicinity of the heat radiating means; a filter allowing air and light to pass therethrough and catching dust particles of a size which is greater than or equal to a predetermined size, the filter being disposed in the air passage; a light emitting means for irradiating the filter with light; and a light receiving means for detecting a quantity of light passing through or being reflected from the filter.
The estimating means preferably includes an air passage disposed in the vicinity of the heat radiating means; a filter allowing air or light to pass therethrough and catching dust particles of a size which is greater than or equal to a predetermined size, the filter being disposed in the air passage; and pressure sensors provided on the upstream side and the downstream side of the filter.
The ozone purifying apparatus preferably includes means for detecting a vehicle speed, and the diagnosing means corrects a pressure detected by each of the pressure sensors according to the detected vehicle speed, and diagnoses the operating state of the ozone purifying means based on the corrected pressure.
The air passage is preferably configured such that no external light reaches the light emitting means and the light receiving means.
The diagnosing means preferably determines that a purifying characteristic of the purifying means is degraded when the light quantity detected by the light receiving means decreases to a predetermined threshold value or less, and gives a warning.
The airflow detecting means is preferably a wind velocity sensor provided in front of or at the back of the heat radiating means.
The diagnosing means preferably corrects the wind velocity detected by the wind velocity sensor according to the detected vehicle speed, and diagnoses the operating state of the ozone purifying means based on the corrected wind velocity.
The diagnosing means preferably corrects the wind velocity detected by the wind velocity sensor according to the detected vehicle speed and determines that a purifying characteristic of the purifying means is degraded when the corrected wind velocity decreases to a predetermined threshold value or less, the diagnosing means giving a warning.
According to a third aspect of the present invention, there is provided an ozone purifying apparatus for a vehicle, comprising: ozone purifying means provided on the vehicle; first ozone concentration detecting means for detecting a concentration of ozone in air which flows into the ozone purifying means; second ozone concentration detecting means for detecting a concentration of ozone in air which has passed through the ozone purifying means; and degradation detecting means for detecting degradation of the ozone purifying means by using outputs from the first and second ozone concentration detecting means.
With this configuration, the concentration of ozone in air which flows into the ozone purifying catalyst and the concentration of ozone in air which has passed through the ozone purifying catalyst are detected, and the degradation of the ozone purifying catalyst is detected by the detected concentrations of ozone. Accordingly, it is possible to directly detect the purifying ability of the ozone purifying catalyst, and hence to detect the degradation of the ozone purifying apparatus due to various causes, for example, the degradation due to adhesion of adhered matter such as dust or the degradation due to SOx.
The apparatus preferably includes airflow detecting means for detecting an amount of airflow passing through the ozone purifying means, wherein the degradation detecting means detects the degradation of the ozone purifying means according to outputs from the first and second ozone concentration detecting means and an output from the airflow detecting means.
With this configuration, the amount of airflow passing through the ozone purifying means is detected, and the degradation of the ozone purifying means is detected according to outputs from the first and second ozone concentration detecting means and on the detected amount of airflow. Since the characteristic of the ozone purifying apparatus is proportional to a product of the purifying ability of the ozone purifying apparatus and the amount of airflow passing through the ozone purifying means, it is possible to detect the ozone purifying catalyst by totally evaluating the characteristic of the ozone purifying apparatus in consideration of the effect of clogging due to adhesion of dust or the like by detecting an amount of airflow passing through the ozone purifying apparatus, to thereby more accurately detect degradation of the ozone purifying means.
The apparatus preferably further includes ozone supply means for supplying ozone into an airflow passing through the ozone purifying means, on the upstream side of the first ozone concentration detecting means.
With this configuration, ozone is supplied into the airflow passing through the ozone purifying means, on the upstream side of the first ozone concentration detecting means. Therefore, it is possible to accurately detect the purifying ability of the ozone purifying catalyst even if the detection range of the ozone concentration detecting means is narrow.
The apparatus preferably includes a diffusion prevention pipe for preventing diffusion of ozone supplied from the ozone supply means.
The apparatus preferably includes ozone decomposing means for decomposing ozone, which is disposed on the downstream side of the second ozone concentration detecting means.
The apparatus preferably includes a circulation-type diffusion prevention pipe which has an upstream diffusion prevention pipe disposed on the upstream side of the ozone purifying means and a downstream diffusion prevention pipe disposed on the downstream side from the ozone purifying means, the downstream diffusion prevention pipe being connected to the upstream diffusion prevention pipe.
The circulation-type diffusion prevention pipe is preferably provided with wind blowing means for generating an airflow, and the blowing means is operated such that an airflow rate becomes a value suitable for detection of a concentration of ozone by the first and second ozone concentration detecting means.
The apparatus preferably includes moving means for moving the ozone concentration detecting means, the ozone supply means, and the diffusion prevention pipe to a position where none of the ozone. concentration detecting means, the ozone supply means, and the diffusion prevention pipe obstructs an airflow into or from the ozone purifying means when the degradation detection is not executed.